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== Cardiac Blood Vessels ==
 
== Cardiac Blood Vessels ==

Revision as of 09:13, 12 February 2012

Notice - Mark Hill
Currently this page is only a template and will be updated (this notice removed when completed).

Introduction

Developing Blood Vessel

Blood develops initially within the core of "blood islands" in the mesoderm. During development, there follows a series of "relocations" of the stem cells to different organs within the embryo. In the adult, these stem cells are located in the bone marrow. At the time when blood first forms, there are no bones!

Angioblasts initially form small cell clusters (blood islands) within the embryonic and extraembryonic mesoderm. These blood islands extend and fuse together making a primordial vascular network. Within these islands the peripheral cells form endothelial cells while the core cells form blood cells (haemocytoblasts).

Recent work has shown that the formation of the initial endothelial tube is by a process of coalescence of cellular vacuoles within the developing endothelial cells, which fuse together without cytoplasmic mixing to form the blood vessel lumen.

See also the related pages Placental Villi Blood Vessels and Coronary Circulation Development.

Cardiovascular Links: cardiovascular | Heart Tutorial | Lecture - Early Vascular | Lecture - Heart | Movies | 2016 Cardiac Review | heart | coronary circulation | heart valve | heart rate | Circulation | blood | blood vessel | blood vessel histology | heart histology | Lymphatic | ductus venosus | spleen | Stage 22 | cardiovascular abnormalities | OMIM | 2012 ECHO Meeting | Category:Cardiovascular
Historic Embryology - Cardiovascular 
1902 Vena cava inferior | 1905 Brain Blood Vessels | 1909 Cervical Veins | 1909 Dorsal aorta and umbilical veins | 1912 Heart | 1912 Human Heart | 1914 Earliest Blood-Vessels | 1915 Congenital Cardiac Disease | 1915 Dura Venous Sinuses | 1916 Blood cell origin | 1916 Pars Membranacea Septi | 1919 Lower Limb Arteries | 1921 Human Brain Vascular | 1921 Spleen | 1922 Aortic-Arch System | 1922 Pig Forelimb Arteries | 1922 Chicken Pulmonary | 1923 Head Subcutaneous Plexus | 1923 Ductus Venosus | 1925 Venous Development | 1927 Stage 11 Heart | 1928 Heart Blood Flow | 1935 Aorta | 1935 Venous valves | 1938 Pars Membranacea Septi | 1938 Foramen Ovale | 1939 Atrio-Ventricular Valves | 1940 Vena cava inferior | 1940 Early Hematopoiesis | 1941 Blood Formation | 1942 Truncus and Conus Partitioning | Ziegler Heart Models | 1951 Heart Movie | 1954 Week 9 Heart | 1957 Cranial venous system | 1959 Brain Arterial Anastomoses | Historic Embryology Papers | 2012 ECHO Meeting | 2016 Cardiac Review | Historic Disclaimer

Some Recent Findings

Adult human cardiovascular system
  • Specification of arterial, venous, and lymphatic endothelial cells during embryonic development [1] "The groundbreaking discovery about arterial and venous expression of ephrinB2 and EphB4, respectively, in early embryonic development has led to a new paradigm for vascular research, providing compelling evidence that arterial and venous endothelial cells are established by genetic mechanisms before circulation begins. For arterial specification, vascular endothelial growth factor (VEGF) induces expression of Notch signaling genes, including Notch1 and its ligand, Delta-like 4 (Dll4), and Foxc1 and Foxc2 transcription factors directly regulate Dll4 expression. Upon activation of Notch signaling, the Notch downstream genes, Hey1/2 in mice or gridlock in zebrafish, further promote arterial differentiation. On the other hand, the orphan nuclear receptor COUP-TFII is a determinant factor for venous specification by inhibiting expression of arterial specific genes, including Nrp1 and Notch. After arterial and venous endothelial cells differentiate, a subpopulation of venous endothelial cells is thought to become competent to acquire lymphatic endothelial cell fate by progressively expressing the transcription factors Sox18 and Prox1 to differentiate into lymphatic endothelial cells."
  • Developmental origin of smooth muscle cells in the descending aorta in mice[2] "Aortic smooth muscle cells (SMCs) have been proposed to derive from lateral plate mesoderm. ....(these results) suggested that all SMCs in the adult descending aorta derive from the somites, whereas no contribution was recorded from lateral plate mesoderm."
  • Notch ligand Jagged1 is required for vascular smooth muscle development[3] "The Notch ligand Jagged1 (Jag1) is essential for vascular remodeling. ...Jag1 null phenotype. These embryos show striking deficits in vascular smooth muscle, whereas endothelial Notch activation and arterial-venous differentiation appear normal."

Endothelial Progenitors

Recent work has shown that the formation of the initial endothelial tube is by a process of coalescence of cellular vacuoles within the developing endothelial cells, which fuse together without cytoplasmic mixing to form the blood vessel lumen. [4]

Endothelial Tube Formation

Blood vessel lumen formation.jpg

Blood vessel lumen formation

Vessel Specification

The following data is from a recent review.[1]

Arterial Specification

Factor Function
Shh Loss of Shh results in lack of arterial identity in zebrafish. Shh acts upstream of VEGF.
VEGF VEGF acts downstream of Shh signaling to activate Notch via the PLCγ/ERK pathway in zebrafish. Mutant mice expressing only VEGF188 lack arterial differentiation.
Nrp1 Null mice display impaired arterial differentiation. Nrp1 is involved in a positive feedback loop of VEGF signaling.
Notch Notch acts downstream of Shh and VEGF signaling in zebrafish. Notch1; Notch4 mutant mice have abnormal vascular development.
Dll4 Null mice lack arterial specification.
Dll1 Null mice fail to maintain arterial identity.
Hey1/2 (Grl) Null mice lack arterial specification. Lack of grl in zebrafish results in loss of arterial specification.
Foxc1/c2 Foxc1; Foxc2 mutant mice lack arterial specification. Foxc1 and Foxc2 directly regulate Dll4 and Hey2 expression. Foxc1 and Foxc2 are also involved in lymphatic vessel development.
Sox7/18 Lack of Sox7/18 results in loss of arterial identity in zebrafish.
Snrk-1 Snrk-1 acts downstream or parallel to Notch signaling in zebrafish.
Dep1 Dep1 acts upstream of PI3K in arterial specification in zebrafish.
Crlr Shh regulates VEGF activity by controlling crlr expression in zebrafish.
EphrinB2 Null mice lack boundaries between arteries and veins. EphrinB2 is involved in lymphatic vascular remodeling and maturation.

Venous Specification

Factor Function
COUP-TFII COUP-TFII suppresses arterial cell fate by inhibiting Nrp1 and Notch. COUP-TFII also interacts with Prox1 to regulate lymphatic gene expression.
EphB4 Null mice lack boundaries between arteries and veins.

Lymphatic Specification

Factor Function
Sox18 Null mice fail to specify lymphatic endothelial cells. Sox18 induces Prox1 expression.
Prox1 Prox1 induces lymphatic markers and maintains lymphatic cell identity.

Vascular Endothelial Growth Factor

Growing blood vessels follow a gradient generated by tagret tissues/regions of Vascular Endothelial Growth Factor (VEGF) to establish a vascular bed. Recent findings suggest that Notch signaling acts as an inhibitor for this system, preventing sprouting of blood vessels.

Notch is a transmembrane receptor protein involved in regulating cell differentiation in many developing systems.

Links: OMIM - VEGFA | OMIM - Notch

Regulators of Growth

The following data is from a review article on ovary vascular development.[5]

Stimulators of Angiogenisis

  • Peptide growth factors
    • Vascular endothelial growth factor-Aa,b, -Bb, -Cb, -D
    • [-E], -F (VEGF-Aa,b, -Bb, -Cb, -Db, -E, -F)
    • Placenta growth factor (PlGF)
    • Angiopoietin-1 (Ang-1)
    • Angiopoietin-2 (Ang-2) [modulator in the presence of angiogenic activity]
    • Acidic fibroblast growth factor (FGF-1)
    • Basic fibroblast growth factor (FGF-2)
    • Platelet-derived growth factor (PDGF)
    • Transforming growth factor-a (TGF-a)
    • Transforming growth factor-b (TGF-b)
    • Hepatocyte growth factor (HGF)
    • Insulin-like growth factor-I (IGF-I)
  • Multifunctional cytokines/immune mediators
    • Tumour necrosis factor-a (low-dose)
    • Monocyte chemoattractant protein-1 (MCP-1)
  • CXC-chemokines
    • Interleukin-8 (IL-8)
  • Enzymes
    • Platelet-derived endothelial cell growth factor
    • (PD-ECGF; thymidine phosphorylase)
  • Angiogenin (ribonuclease A homologue)
  • Hormones
    • Oestrogens
    • Prostaglandin-E1, -E2
    • Follistatin
    • Proliferin
  • Oligosaccharides
    • Hyaluronan oligosaccharides
    • Gangliosides

Inhibitors of Angiogenisis

  • Peptide growth factors and proteolytic peptides
    • Angiopoietin-2 (Ang-2) [in the absence of angiogenic activity]
    • Angiostatin
    • Endostatin
    • 16 kDa prolactin fragment
    • Laminin peptides
    • Fibronectin peptides
  • Inhibitors of enzymatic activity
    • Tissue metalloproteinase inhibitors
    • (TIMP-1, -2, -3, -4)
    • Plasminogen activator inhibitors
    • (PAI-1, -2)
  • Multifunctional cytokines/immune mediators
    • Tumour necrosis factor-a (high-dose)
    • Interferons
    • Interleukin-12
  • CXC-chemokines
    • Platelet factor-4 (PF-4)
    • Interferon-gamma-inducible protein-10 (IP-10)
    • Gro-beta
  • Extracellular matrix molecules
    • Thrombospondin
  • Hormones/metabolites
    • 2-Methoxyestradiol (2-ME)
    • Proliferin-related protein
  • Oligosaccharides
    • Hyaluronan, high-molecular-weight species

Histology

Capillary Electron Microscopy

Blood capillary EM 01.jpg Blood capillary EM 02.jpg
Blood Capillary Electron Micrograph[6]

A blood capillary lumen (lu) lined by an endothelial cell (en) is surrounded by a continuous basal lamina (arrowhead) in which is incorporated a pericyte (p).

Extracellular matrix collagen bundles at top of image.

Scale bar 1 μm

Blood Capillary Electron Micrograph

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=Arteries

Cardiac Blood Vessels

Earliest vessels in the heart wall develop subepicardially (beneath the outside surface of the heart) near the apex at Carnegie stage 15, which then extends centripetally and at stage 17 coronary arterial stems communicate with the aortic lumen.

(Text modified from: [7])

References

  1. 1.0 1.1 <pubmed>20238301</pubmed>| PMC2899674
  2. <pubmed>18417617</pubmed>
  3. <pubmed>18245384</pubmed>
  4. <pubmed>11827993</pubmed>
  5. <pubmed>11141338</pubmed>
  6. <pubmed>21702933</pubmed>| PMC3141733 | BMC Cell Biol.
  7. <pubmed>8915616</pubmed>

<pubmed>10948449</pubmed> <pubmed>12406884</pubmed>

Search Pubmed Now

Click on the listed keywords below (used to search the external database) the most current references on Medline will be displayed.

[TITL+development[WORD]+review[WORD]&doptcmdl=DocSum blood[TITL]+development[WORD]+review[WORD]]

Blood Vessel Development Terms

  • angioblasts stem cells in blood islands generating endothelial cells
  • angiogenesis the formation of blood vessels also called vasculogenesis in the embryo
  • blood islands earliest sites of blood vessel and blood cell formation, seen mainly on yolk sac chorion
  • vascular endothelial growth factor (VEGF) protein growth factor family that stimulates blood vessel growth, a similar factor can be found in the placenta (PIGF).

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2020, April 2) Embryology Cardiovascular System - Blood Vessel Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Cardiovascular_System_-_Blood_Vessel_Development

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© Dr Mark Hill 2020, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G